1. Technical Field
The present disclosure relates to a wiring board, a semiconductor package, and a semiconductor device.
2. Description of the Related Art
In the related art, a so-called POP (Package On Package) structure has been known as a structure for stacking semiconductor packages on each other. There has been proposed a technique capable of increasing the density of each wiring layer in a semiconductor device having such a POP structure (e.g. see Japanese Patent No. 5662551 (JP5662551B1)). For example, a semiconductor package has been proposed as a lower-side semiconductor package. In the semiconductor package, high-density wiring layers including insulating layers in each of which a photosensitive resin is layered are formed on low-density wiring layers including insulating layers in each of which a thermosetting resin is layered, and a semiconductor chip is flip-chip mounted on pads formed in an uppermost one of the high-density wiring layers. In this type of semiconductor device, POP connection pads are formed in the uppermost high-density wiring layer, and an upper-side semiconductor package is stacked and bonded on the connection pads.
In the aforementioned semiconductor device, the POP connection pads are formed on the photosensitive resin which is mechanically brittle. Therefore, when an external force is applied to the connection pads in order to stack and bond the upper-side semiconductor package on the lower-side semiconductor package in the semiconductor device, resin fracture such as cracking is apt to occur in the photosensitive resin which receives the load imposed on the connection pads.